


Compatibilism

by Fangirling_FTW



Series: Destiel One-Shots [12]
Category: Supernatural
Genre: ALL THE FLUFF, AU, Ficlet, Fluff, M/M, SO MUCH FLUFF, Sastiel - Freeform, TA Sam Winchester, Teacher Castiel
Language: English
Status: Completed
Published: 2017-04-03
Updated: 2017-04-03
Packaged: 2018-10-14 14:17:37
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,991
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10538229
Author URL: https://archiveofourown.org/users/Fangirling_FTW/pseuds/Fangirling_FTW
Summary: Sam fills his time his last semester before law school by signing up for a TA position...and ends up with the history department's "hottest teacher on campus."  The only thing he's going to have to worry about is falling asleep in front of the students... right?





	

**Author's Note:**

> I wanted to give Sastiel a try because someone posted a student!Sam teacher!Cas edit after Misha did his lecture and you know what? I HAVE NO REGRETS!! I also know I'm one of hundreds writing a teacher!Cas fic after the lecture but I also DON'T CARE! 
> 
> *slides on sunglasses* *struts off into the distance*
> 
> Remember if you enjoy this to comment! Leave me a prompt, if something strikes my fancy and I'm facing writer's block I might do something like this based on your prompt too!
> 
> Also, I'm disappointed that there are no pre-populated Castiel/ Sam Winchester tags... poor sastiel... no love for their ship :(

Sam hadn't been in the history building in years, not since his first semester of college.  The musty old building reminded him of his Uncle Bobby’s house, filled with books almost as old as the topics they discussed.  He hitched his messenger bag higher on his shoulder as a gaggle of freshman girls pushed past him, tittering to each other in excited whispers as they walked towards the end of the hallway.

_ Guess I know where Dr. Novak’s classroom is. _

Sam had just finished pre-law, and would be graduating at the end of this fall semester.  It would have been in the spring after his 5 years were up, but he'd neglected a couple of his standard math and science requirements to graduate, so he was stuck with a 12 hour credit schedule and a lot of extra time.  He thought signing up for a TA position would be a way to spend more time with his professors, sort of a cheat to get to retake their classes for free, but to his annoyance, they overbooked TA’s for his department.  Sam just let them place him somewhere else, the work study money was crap but it would pay for nights out to dinner with his friends.  So Monday, Wednesday, and Friday, he would be spending most of the day here with a history professor, trying not to doze off in front of the students.

Sam didn't know much about Dr. Novak, just that he was young for a teacher, and only just taking on teaching Master’s students for the first time.  He had requested a TA for his lower level courses, freshman and sophomore history mostly, though he also taught some of the religious studies classes as well, like philosophy.  

Dr. Novak did have a reputation for one thing: apparently he was the “hottest teacher on campus”.

When Sam walked into the Hist 101 classroom, most of the students were in their seats already, and they all turned to face him when he walked in.

“I thought Laney said he had  _ blue  _ eyes,” one of the nearby girls whispered to her friend.  Sam set his jaw, walking up to the front of the class and the desk set up for him to find a note sitting there.  It was written in a gorgeous flowing handwriting, which put Sam’s chicken scratch to shame.

 

_ Mr. Winchester, _

_ I apologize, I had some difficulty this morning and will be tardy for my first class.  If you could, please hand out the syllabus and take roll, I will be there as fast as possible. _

_ Dr. Novak _

 

Sam glanced at the teacher’s podium to see the student roster sitting there and a stack of papers next to it.  He agitatedly brushed a hand through his hair, checking his watch to see that class had technically officially started.

_ I didn't sign up for this, _ Sam grumbled to himself.  He walked up to the podium, and one of the kids raised their hand.

“Excuse me, Dr. Novak?” he asked.

“Uh, no,” Sam said, clearing his throat which was apparently hoarse.  “I'm, uh, I'm Sam, his TA.”

“I don't think I'm supposed to be in this class,” the guy went on to say anyway.  Sam picked up the roster.

“Let's go through this here, and find out,” Sam said, trying to suck it up and be a professional.  It was one thing to put him in a mock court room with his peers, he could handle that pressure with no problem.  He wasn't a teacher, and he wasn't used to being looked at like an authority figure, that was his brother’s job.  He called out roll, marking next to the names of the students who weren't there, and writing in names of students who were but weren't on the list.  The guy who had spoken out was on the list, and tried to argue again, but Sam managed to shut up by pointing out he could talk to Dr. Novak after class.  As he passed out the syllabi, some of the girls watched him a little too closely, and Sam shifted awkwardly.  He was used to girls looking at him, (and some guys too), he had a strong physique and a sharp cut to his jawline, but the power dynamic made things feel...inappropriate.  Yeah, he was 23 and they were 18, but still…

“My apologies, students, I'm afraid I had something come up,” a deep voice announced loudly and confidently into the room.  “Thank you, Mr. Winchester,” Dr. Castiel Novak said as Sam walked back to the front of the room.  Even though Sam had almost five inches of height on the guy, he had a presence that made Sam feel like a kid all over again.  And the whispering girl from earlier was right, he did have bright blue eyes, a deep intelligence behind them that made them seem older than they were.

“Yeah, course,” Sam said, handing him the spare syllabi and quickly sitting at his TA desk.

After class, Sam waited for all the students to file out, standing awkwardly behind Dr. Novak until they’d all gone.

“Well, Mr. Winchester,” Dr. Novak said with a smile, “I know this may not be what you originally had in mind for this semester, but your help will be invaluable to me.”  He offered his hand and Sam hesitated awkwardly a moment before shook it.

“Sure, yeah.  Uh, you can call me Sam,” he said smiling back.

“Okay, Sam,” Dr. Novak nodded.  He turned his back to Sam, rooting through his briefcase and pulling out another paper.  “I’ve made you a list of responsibilities, for the first couple weeks I obviously won’t have too much work for you.”  Sam nodded and took the sheet, scanning over it.  “Sam?”  He glanced back up at the professor, whose blue eyes were narrowed in concern.  “I know this is menial labor for someone headed into law school, but while my history lessons may not be that exciting, I do hope you enjoy philosophy.  The ability to argue could come in handy in a courtroom.”  Sam smiled genuinely, glad that Dr. Novak understood how he felt about this job.

“I look forward to it,” Sam agreed.  Dr. Novak’s face relaxed into a smile.

“Okay, I don’t have anything else for you today, so I’ll see you Wednesday?”

“Wednesday,” Sam echoed, walking back to his desk, tucking his paper in his bag and turning for the door.

 

For the first two months, Sam sat in on Dr. Novak’s lectures without too much to do.  He copied notes from his handwritten lesson plans into Word documents, formatted handouts and test papers, logged where each class had gotten to, and worked on grading some basic homework assignments.  The history classes were mildly intriguing, Dr. Novak taught those classes with passion, but history was history.  Sam appreciated it but couldn't quite stay connected after three class periods of it.  However, Sam really did enjoy the philosophy classes, even though they were after lunch he found himself paying rapt attention to Dr. Novak.  Sam liked his dry sense of humor, once he started to understand it, and admired the way he could deliver any line completely cool and straight faced.  Some of the professor’s fan girls had taken a liking to Sam, and started hanging around his desk after class to try anything and everything to get the upperclassman to notice them.  Sam got the distinct impression that Dr. Novak was amused by the whole thing, and maybe a bit relieved that his admirers had turned their attention to someone else.  Sam fumbles awkwardly to get away every single day, a blushing and flustered mess, and Dr. Novak just smirks on his way out the door.

 

The day of Dr. Novak's first test, Sam got an email letting him know he didn't need to show up until after his final class was done, much to Sam’s relief.  Sam called his brother, Dean, who lived just off campus, and they went out for lunch and a few games of darts before Sam had to return to work.  Sam had his brother drop him off at the history building and made his way to Dr. Novak’s office, dropping onto the couch to wait for him to return from class.

Sam hadn't spent any real amount of time in Dr. Novak's office so far, just in passing to hand off papers or check in before leaving.  The walls were covered mostly by bookshelves and filing cabinets, his tiny desk crammed in the corner with just enough room for the couch Sam was sitting on.  A couple of the shelves had pictures on them, Dr. Novak at his Doctoral graduation, another of him standing with a woman with blonde hair and a kind smile, and another with a young girl, maybe 8 years old, with wavy blonde hair.  Sam stood and walked over to the photos, unaware that Dr. Novak was married.

“Sorry to keep you waiting,” the professor huffed as he hurried into his office.  Sam quickly turned away from the photos, flushing at being caught prying into Dr. Novak’s personal space.  Dr. Novak’s arms were full of papers, and his briefcase dangled precariously from a couple fingers as the professor made his way around his desk.  

“It's no problem, Dr. Novak, I haven’t been here long,” Sam shrugged, walking back to the couch and sitting.  Dr. Novak glanced at the photos as he carefully set his briefcase down.

“I believe my niece is a little young for you,” Dr. Novak said evenly, but Sam heard the amusement in his tone.

“I didn't mean to be nosy,” Sam started to apologize, but Dr. Novak waved it away.

“It's alright, Sam.”  He pulled down the photo of him with the blonde woman, smiling at it fondly.  “I don't think you’ll freak out as much as my fan club will, finding out I have a twin brother.”

“That's your brother?” Sam laughed.  “You guys really are identical.”

“In appearance, but in personality, we couldn't be more different.”  Dr. Novak put the photo back down, turning for the papers on his desk.  He attempted to pick up a stack, but Sam could see the papers slipping even before he lifted it.  He jumped up and reached out, wrapping his own hand around the stack just before they went everywhere.  “Th-thanks,” Dr. Novak mumbled, and when Sam looked up from the papers, he found he was standing rather close to the blushing, wide eyed professor.  Sam watched his throat work as he swallowed hard, and Sam took the stack of papers from him, stepping back to sit on the couch.

“No problem, Dr. Novak,” he assured him.

“You can...you can call me Castiel if you want.  I mean, when we're alone like this- well, you know, when no students are around-”

“Okay, Castiel,” Sam cut off his nervous rambling with a smile.  “I take it I'm going to be grading the multiple choice?”

“Huh?  Oh, yes,” Castiel snapped back into teacher mode, pulling a copy of the answer key out for Sam, walking around the desk and handing it to him, along with a stack of small sticky notes.  “Just put the number of questions correct on the notes and I'll factor it in when I'm done with the short answer questions.”  Castiel lingered there for a moment, looking down at Sam before spinning on his heel and dropping into his desk chair, ducking his head with a blush.

Sam watched him out of the corner of his eye as he worked on the tests he'd been given.  Blushing and flustered Castiel was something he hadn't ever expected to see.  He always seemed so controlled and steady in front of his students, even when they tried to rile him up, so to see Castiel blushing because he almost dropped a stack of tests was...well, it was kinda cute.

 

Midterms came and went, as did fall break. 

Sam had become invested in the course material, and started to actually participate in the philosophy classes that Castiel taught.  He’d let the students take the first crack at a question, but if none of them were responding, he’d speak up to keep the discussion flowing.  Castiel made a show of scolding him and reminding him he wasn’t really taking the class, but after class was done they’d continue talking about it, Castiel was obviously excited that Sam was taking an active interest in the topic.  Sam had to agree that it made sense to him how philosophy would help in the courtroom, and he was fairly disappointed that he hadn’t thought to actually take the class for credit.  

Sam started to get to know Castiel a bit more personally as well.  He found out that even though he was teaching Masters level classes, he was only 30, having breezed quickly through his own Masters degree and his Doctorate.  His brother, Jimmy, and his family were all Castiel had, Sam’s parent’s divorce suddenly didn't seem like that big of a deal.  Castiel had an affinity for religion and its role in history, and also had a fascination with  _ bees _ of all things.  Every little detail that the two of them shared made Sam realize that in spite of the confident authoritative persona he projected, Castiel was just like any other guy, with his insecurities and his faults.

Sam also started to realize that it was quite possible Castiel had a  _ crush  _ on him.  He started testing his theory, wearing his shirts unbuttoned slightly, trying a new cologne, casually running his hand through his hair when he knew Castiel was watching, and even brushing his arm against him on occasion.  As expected, Castiel managed to stay cool and collected in front of his students, but their interactions when they were alone made it clear that Sam’s mild flirtation was not going unnoticed.  Castiel was flustered at the best of times, and at the worst had difficulty even looking at Sam.  

However, Castiel wasn’t the only one starting to crush on the other.

Sam kept up the teasing because he wanted to see Castiel’s blushes, wanted to see the shy smiles and the nervous way he’d rub his neck.  He really enjoyed getting Castiel worked up talking about something he believed in passionately, because his eyes would shine and the smile would wrinkle the skin around his nose.  

 

It wasn’t until Sam caught himself daydreaming about Castiel while peeling potatoes over Thanksgiving break that he fully accepted he  _ liked  _ Castiel.  A whole hell of a lot.

“Okay, what’s going on with you.”  Dean cornered Sam in the dining room, turning a chair around to face his little brother and the stack of potatoes that was still sitting in front of him.

“It’s nothing, Dean.”

“Uh, huh, nothing.  So ‘nothing’ is why you haven’t finished with the potatoes yet?  Mom wants to get dinner done before, you know, dinner time.”  Sam set the peeler down, tossing the finished potato in the bowl with the meager few he’d managed so far. 

“Okay, fine,” Sam sighed.  “I kind of like someone, and I think...I think they like me too.”

“How is that a problem?” Dean chuckled, picking up the peeler and hacking away at a potato.

“Because they’re a professor,” Sam said simply.  Dean choked on a laugh, nearly dropping the potato he was peeling.

“Dude, seriously?  My little brother hitting on a teacher?”

“It’s not funny,” Sam snapped.  Dean swallowed his mirth, putting his finished potato in the bowl.

“Sorry, Sammy, you’re right.”  Sam snatched the peeler back, picking up his next potato. 

“He’s not that much older than me, really, only seven years-”

“Wait, ‘he’?!” Dean interrupted.  Sam flushed but nodded, and Dean raised his eyebrow with an approving nod.  “Okay, he.”

“He’s not even my professor, he’s the guy I’m doing the TA for.  And I mean, he’s not married, or anything, but...I don’t know.”  Dean handed Sam a fresh potato when he finished the one he was working on.

“Little Sammy, always afraid of breaking the rules,” Dean teased.

“Don't be an ass,” Sam grunted, taking out his frustration on the new potato.  Dean’s laugh faded into silence, watching Sam work until he'd picked up another potato.

“You’re really serious about this guy, aren’t you?” Dean asked.  Sam sighed heavily, knowing that would be the only answer his brother would need.  Dean shrugged, pushing himself to his feet and putting his chair back.  “If you think he’ll make you happy then do it, Sam.  Fuck anyone who thinks less of you.”  And with that bit of wisdom, Dean walks out of the room, leaving Sam to his potatoes and his racing thoughts.

 

The first day of class after break, Sam gets to the history building early, hoping to catch Castiel before any students arrive.  To his disappointment, the gaggle of girls he's dubbed the “Fan Club” are waiting in the building already, pushing past security into the classroom once it's unlocked.  Sam flushes, because he doesn't really have a good excuse for getting there as early as he did, but he plays it off by waking in the classroom with his own homework and pulling it out to look it over again.

He tries not to listen to them talk, but in the quiet classroom he can't help overhearing what they're whispering about.

_ “...Mr. Winchester was here early again, did you see?” _

_ “Waiting for his boyfriend to show up, omg how cute!” _

_ “He is such a bottom, being all obedient and trying to please Dr. Novak-” _

Sam barely managed not to choke on his own tongue, and thankfully his reaction was masked by the rest of the class walking in.  He wasn't dumb, he knew some of the students might catch on to his and Castiel’s flirtation, but they didn't know the real Castiel, so they had no idea how badly they had their assumptions switched about who would be the... _ dominant _ personality in their relationship.  When Castiel walks in, the girls giggle, and Sam barely manages not to blush as he walks up to say hello.

“Sam!  How was your break?” Castiel asked, smiling at him as he walked up.

“Great,” Sam nodded, patting Castiel’s shoulder.   _ Might as well give those girls something to talk about _ .  Sam leaned in a bit closer to Castiel to avoid being overheard.

“At the end of classes today, could I have a word in your office?”  He watched in amusement as Castiel’s exterior almost cracked, the professor’s jaw clenching tightly.

“Of course,” he muttered back, turning his attention back to his lecture notes.  Sam smiled, pleased with himself, and settled in at his desk.

The entire lecture, his eyes were on Castiel, watching how he shifted on his feet as he talked, the way he moved his hands, the way he’d lick his lips periodically when he paused to let the students take notes.  He really was a beautiful man, now that Sam was letting himself admire him, and when he bent to pick up the marker he'd dropped Sam got a rather nice view of his pants pulling tight around his thighs and backside.   _ Thank god for jogging. _

As the day and Castiel’s classes went on, he was caught staring more than once by Castiel, but instead of playing it off he'd just smirk, getting closer and closer to breaking Castiel’s composure.  During Castiel’s last philosophy class, he's lecturing on free will versus determinism.  The class actually gets into the debate, on whether or not you have control over your life or if choice was an illusion and your life was decided for you.  Castiel is enjoying having such a good response from his class, he's right on the verge of smiling, his eyes wide and bright, and it kind of takes Sam’s breath away.  Castiel mentions offhandedly a school of thought called “compatibilism”, the idea that both free will and determinism exist together, and since no one else in the class seems to give it much thought, Sam looks it up himself.

By the time class is done, he's got his game plan set out; now it was just a matter of Castiel’s reaction.  

Castiel hardly looks at him as they walk to his office, fumbling with his briefcase the moment they step inside.

“What was it you wanted to talk about?” he asked Sam nervously.  Sam closed the door behind him, and Castiel visibly paled.

“I feel like you left compatibilism out of your lecture,” Sam said evenly, approaching the side of Castiel’s desk as the professor pretended to go through some essays.

“There aren't many who follow that school of thought.  This is an entry level class, it's not as pertinent,” Castiel mumbled.  Sam stepped closer, into his personal space, and Castiel’s movements stilled, his eyes still focused on his desk.

“See, I believe it could work,” Sam said quietly.  “It was my free will, my choice that made me take this TA assignment, when I could have turned it down easily with no penalty.”  He ran his hand over Castiel’s shoulder, up along the back of his neck, and he didn't miss the way Castiel shuddered.  “But once I’d made that choice, this was inevitable,” Sam continued, “there was no way I was going to avoid feeling like this about you.”

“Sam,” Castiel breathed, his voice strained, “please, I can't-”

“Can't what?” Sam asked, stepping closer. 

“You're a student, and-”

“In three weeks I won't be,” Sam pointed out, raising his other hand to turn Castiel gently by the shoulders.  

“Look, I don't want either of us to get in trouble, just-” Castiel was cut off as Sam’s thumb traced the line where Castiel’s jaw met his neck.

“I'm not your student, I’m graduating in three weeks, you’re only 7 years older than me…”. Cas turned his head into Sam’s touches, and Sam’s heart leapt into his throat.  “Come on, Castiel.  Tell me what's really holding you back.”  Castiel refused to look up at him, his eyes focused straight ahead and therefore at the neck of Sam’s shirt.

“I’ve, I've never...dated a man before.”  Castiel finished the sentence on a rush of breath, his cheeks bright red and his hands clenched at his side.  Sam grinned, running his fingers under Castiel’s chin and lifting his eyes.

“Me neither,” Sam admitted.  Castiel's eyes widened comically and Sam dropped his hands, grabbing hold of Castiel’s wrists gently and moving him over to the couch.  “We’re on even footing here, Castiel.”  Sam dropped to sit on the couch, tugging until Castiel gave in and let Sam position him in his lap facing him.  

“Y-you can call me Cas, it's what my friends call me,” he stammered.  

“Okay, Cas,” Sam agreed.  Cas smiled, shy and embarrassed and beautiful, and Sam lifted Cas’ arms to his shoulders, wrapping his left arm around Cas’ back to pull him close.  “Cas, can I kiss you?” he asked softly.  Cas wet his lips, nodding and Sam ran his hand along Cas’ jaw, pulling him in for a soft caress of lips on lips.  Cas gasped when Sam pulled away, his arms tightening around Sam’s neck.

“Again?” he asked.  Sam grinned and relented.  

Again and again, their lips, tongues, teeth met, till Cas was rocking against him and their hair was tangled and mussed.

“Three weeks, you said?” Cas gasped against Sam’s chin, fingers drawing gentle patterns on the back of his neck.  Sam nodded and pressed a chaste kiss against the tip of Cas’ nose, resting their foreheads together.

“Or, you know, I could quit my TA now.  Take you back to my apartment…”  Cas’ breath hitched, his hips twitching against his will.

“You're very persuasive, Mr. Winchester,” Cas hummed.  Sam smirked, leaning in to nip at Cas’ lip.

“Oh, you don't know the half of it,” Sam hummed deep in his chest.

But later that night Cas definitely found out.

**Author's Note:**

> Remember to comment my darlings!


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